In the field of semiconductor material processing, semiconductor material processing apparatuses including vacuum processing chambers are used for performing various plasma processes, such as etching of materials on substrates. The effectiveness of these etch processes is often dependent on the ability to control the temperature conditions at certain locations of the processing chambers.
Current temperature control consists of a cooled top plate and heated thermal control plate. The heater or heating elements within the thermal control plate is used to preheat the silicon upper electrode (or showerhead electrode) prior to processing. During processing plasma will heat the electrode to a steady state temperature based on the process power and thermal choke configuration. The heater is used to preheat the electrode prior to plasma processing. Preheating the electrode increases etch uniformity by limiting the chamber variables during processing. Without preheating the polymer deposition in the chamber would change until the electrode reaches steady state temperature.
With the current trend to use higher and higher process powers, it would be desirable to have a temperature control plate, which creates a variable conductance heat choke to the top plate.